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Evidence-Based Practice

Evidence-Based Practice

Levels of Evidence

One way to organize the different types of evidence involved in evidence-based practice research is the levels of evidence pyramid. The pyramid includes a variety of evidence types and levels.

  • Filtered resources
    • systematic reviews
    • critically-appraised topics
    • critically-appraised individual articles
  • Unfiltered resources
    • randomized controlled trials
    • cohort studies
    • case-controlled studies, case series, and case reports
  • Background information, expert opinion

 

 

Using this Guide

The levels of evidence pyramid provides a way to visualize both the quality of evidence and the amount of evidence available. For example, systematic reviews are at the top of the pyramid, meaning they are both the highest level of evidence and the least common. As you go down the pyramid, the amount of evidence will increase as the quality of the evidence decreases.

Starting from the top, or point, of the pyramid to the base, the pyramid is broken into 7 sections stacked on top of each other. The quality of information is highest at the top of the pyramid, and decreases as you move down to the base.

Levels of Evidence pyramid.  See text alternative for explanation

Text Explanation

Source:  EBM Pyramid and EBM Page Generator, copyright 2006 Trustees of Dartmouth College and Yale University. All Rights Reserved.
Produced by Jan Glover, David Izzo, Karen Odato and Lei Wang.

Find the Evidence

META-SEARCH ENGINES

SYSTEMATIC REVIEWS and META-ANALYSES

EVIDENCE GUIDELINES and SUMMARIES

CLINICAL RESEARCH CRITIQUES

CASE REPORTS/SERIES, PRACTICE GUIDELINES, etc.

Thanks to ...

Joanne Rich at the Health Sciences Library at the University of Washington, for sharing her guide on evidence-based practice with us!